Learn Hardcore Indonesian: Saya mengatur waktu belajar dan istirahat secara seimbang. - I manage my study time and rest time in a balanced way.

mengatur waktu is a very common collocation meaning to manage time.
mengelola also means to manage, but it sounds a bit more formal and is often used for managing something bigger, like mengelola perusahaan (manage a company) or mengelola keuangan (manage finances).
menyusun is more like to arrange / to put together / to compose, often for things like menyusun rencana (to draw up a plan) or menyusun laporan (to compile a report).
menyeimbangkan means to balance something.
For example:
- Saya menyeimbangkan waktu belajar dan istirahat.
  I balance my study time and rest.

In your original sentence, mengatur emphasizes planning and organizing your time, not just keeping the two sides equal like menyeimbangkan would. Both are correct, but the nuance is slightly different.

Why is it waktu belajar dan istirahat and not waktu belajar dan waktu istirahat? Is the second one wrong?

Both are grammatically correct, but the style is different:

waktu belajar dan istirahat
Literally: time for study and rest.
Here waktu is understood to apply to both belajar and istirahat. This is natural and not ambiguous in Indonesian.
waktu belajar dan waktu istirahat
Literally: study time and rest time.
This repeats waktu and sounds slightly more formal or more emphatic, as if you really want to stress that these are two separate blocks of time.

In everyday speech and writing, Indonesians often avoid repeating the same noun if the meaning is clear, so waktu belajar dan istirahat sounds very natural.

Is belajar here a noun or a verb? What about istirahat?

Indonesian is quite flexible: many words can function as both verbs and nouns, depending on context.

In waktu belajar dan istirahat:

belajar literally means to study, but in this phrase it behaves like study time (a noun phrase).
istirahat literally means to rest or rest, and here it functions like rest time.

So the whole phrase can be understood as:

waktu belajar → study time
(waktu) istirahat → (time for) rest

You could also use more explicitly nominal forms, but they are less common in everyday speech:

waktu untuk belajar dan beristirahat
waktu pembelajaran dan waktu istirahat

The original version is more natural and concise.

What exactly does secara mean in secara seimbang?

secara is a word used to turn an adjective into an adverbial phrase, similar to adding -ly in English.

seimbang = balanced (adjective)
secara seimbang = in a balanced way (adverbial phrase)

Other examples:

perlahan = slow → secara perlahan = slowly
formal = formal → secara formal = formally
tidak sengaja = unintentional → secara tidak sengaja = accidentally

So in your sentence, secara seimbang describes how you manage your time.

Can I say dengan seimbang or just seimbang instead of secara seimbang? Are they all correct?

All three are possible, with small differences in style:

secara seimbang
- Very clear adverbial phrase.
- Neutral, common in both spoken and written Indonesian.
- Fits perfectly in your sentence.
dengan seimbang
- Also means in a balanced way.
- Slightly more casual and less common than secara seimbang in this kind of sentence, but still correct.
Just seimbang
- You could say: Saya mengatur waktu belajar dan istirahat seimbang.
- This is understandable, but many speakers would prefer to add secara or dengan here.
- Without secara or dengan, seimbang sounds a bit more like a predicate adjective (describing a state) than a clear manner adverb.

The safest and most natural choice in this context is secara seimbang.

Where can secara seimbang go in the sentence? Can I move it to another position?

The most natural position is exactly as in your sentence:

Saya mengatur waktu belajar dan istirahat secara seimbang.

You can move it, but some placements sound more formal or less natural:

Saya secara seimbang mengatur waktu belajar dan istirahat.
- Grammatically possible.
- Sounds more written/formal and a bit stiff in everyday conversation.
Secara seimbang, saya mengatur waktu belajar dan istirahat.
- Also possible.
- Feels like written style (for essays, articles, etc.).

So:

For everyday natural Indonesian, keep secara seimbang at the end.
Moving it to the front or after the subject is more stylistic and formal.

How do we know the tense in this sentence? Could it mean past, present, or future?

Indonesian verbs do not change form for tense, so mengatur can refer to past, present, or future. The tense is understood from context or from time expressions.

Your sentence by itself is most naturally understood as a general habit:

I manage my study and rest time in a balanced way.

To specify time more clearly, you can add time markers:

Saya selalu mengatur waktu belajar dan istirahat secara seimbang.
I always do this. (general habit)
Tadi saya mengatur waktu belajar dan istirahat secara seimbang.
I did this earlier. (past)
Besok saya akan mengatur waktu belajar dan istirahat secara seimbang.
I will do this tomorrow. (future)

Why is the subject Saya used here instead of Aku? What is the difference?

Both Saya and Aku mean I, but they differ in formality and typical context:

Saya
- More formal and polite.
- Used in most writing, in school, in presentations, with strangers, with people you should respect, etc.
Aku
- More informal and intimate.
- Used with close friends, family, in songs, in informal writing, etc.

Your sentence with Aku would be:

Aku mengatur waktu belajar dan istirahat secara seimbang.

That sounds friendly and casual. The version with Saya is neutral and safe in almost any context, especially for learners.

Is this sentence formal or informal overall? Would a native speaker actually say it like this?

The sentence is neutral, leaning slightly formal, and very natural:

The use of Saya is polite and neutral.
The phrase mengatur waktu is very common and natural.
secara seimbang is slightly more formal than everyday casual speech but is still common, especially when talking about habits, health, study habits, etc.

A native speaker might say exactly this, especially in contexts like:

A presentation about study habits.
A written answer in homework or an essay.
An explanation to a teacher or counselor.

In very casual conversation with friends, they might shorten or rephrase it, for example:

Aku usahain waktu belajar dan istirahat itu seimbang.

Could we say Saya menyeimbangkan waktu belajar dan istirahat instead? How is the meaning different?

Yes, you can say:

Saya menyeimbangkan waktu belajar dan istirahat.

This is correct, and it focuses on the act of balancing the two things.

Nuance difference:

Saya mengatur waktu belajar dan istirahat secara seimbang.
- Emphasizes organizing/managing time, with the manner being balanced.
- Think: planning your schedule so it is balanced.
Saya menyeimbangkan waktu belajar dan istirahat.
- Emphasizes directly making the two amounts balanced.
- Think: adjusting one or the other so they are equal, or more proportionate.

In practice, both can be used to express a similar idea, but mengatur waktu is a very common collocation when talking about time management.

Can I omit waktu and just say Saya mengatur belajar dan istirahat secara seimbang?

You can say:

Saya mengatur belajar dan istirahat secara seimbang.

This is grammatically acceptable and understandable. However:

With waktu, it is clear you are managing time:
Saya mengatur waktu belajar dan istirahat secara seimbang.
Without waktu, it sounds a bit more abstract, as if you are arranging the activities of studying and resting, not specifically their time.

Both are possible, but mengatur waktu belajar dan istirahat is the most natural and common phrasing when you mean time management.

Why is dan used here? Could we use serta instead of dan?

In waktu belajar dan istirahat:

dan is the normal word for and joining two elements: belajar and istirahat.

You could also use serta:

waktu belajar serta istirahat

serta:

Is slightly more formal or literary.
Often appears in written texts, speeches, or lists where the style is more elevated.

In everyday speech and neutral writing, dan is more common and perfectly natural. In your sentence, dan is the best default choice.